Inflow from a Cardiopulmonary Assist System to the Pulmonary Artery and Its Implications for Local Hemodynamics-a Computational Fluid Dynamics Study

When returning blood to the pulmonary artery (PA), the inflow jet interferes with local hemodynamics. We investigated the consequences for several connection scenarios using transient computational fluid dynamics simulations. The PA was derived from CT data. Three aspects were varied: graft flow rate, anastomosis location, and inflow jet path length from anastomosis site to impingement on the PA wall. Lateral anastomosis locations caused abnormal flow distribution between the left and right PA. The central location provided near-physiological distribution but induced higher wall shear stress (WSS). All effects were most pronounced at high graft flows. A central location is beneficial regarding flow distribution, but the resulting high WSS might promote detachment of local thromboembolisms or influence the autonomic nervous innervation. Lateral locations, depending on jet path length, result in lower WSS at the cost of an unfavorable flow distribution that could promote pulmonary vasculature changes. Case-specific decisions and further research are necessary.

Development and evaluation of a variable, miniaturized oxygenator for various test methods

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) became an accepted therapy for the treatment of severe acute respiratory distress syndrome and chronic obstructive pulmonary disease. However, ECMO systems are still prone to thrombus formation and decrease of gas exchange over time. Therefore, it is necessary to conduct qualified studies to identify parameters for optimization of ECMO systems, and especially the oxygenator. However, commercially marketed oxygenators are not always appropriate and available for certain research use cases. Therefore, we aimed to design an oxygenator, which is suitable for various test conditions such as blood tests, numerical simulation, and membrane studies, and can be modified in membrane area size and manufactured in laboratory.

METHODS

Main design criteria are a homogeneous blood flow without stagnation zones, low pressure drop, manufacturability in the lab, size variability with one set of housing parts and cost-efficiency. Our newly designed oxygenator was tested comparatively regarding blood cell damage, gas transfer performance and pressure drop to prove the validity of the design in accordance with a commercial device.

RESULTS

No statistically significant difference between the tested oxygenators was detected and our new oxygenator demonstrated sufficient hemocompatibility. Furthermore, our variable oxygenator has proven that it can be easily manufactured in the laboratory, allows to use various membrane fiber configurations and can be reopened easily and non-destructively for analysis after use, and the original geometry is available for numerical simulations.

CONCLUSION

Therefore, we consider this newly developed device as a valuable tool for basic experimental and numerical research on the optimization of oxygenators.

Effects of hypercapnia versus normocapnia during general anesthesia on outcomes: a systematic review and meta-analysis

BACKGROUND

The effect of mild changes in CO₂ levels to organ perfusion and tissue inflammation are well known, whereas an influence of hypercapnia under general anesthesia on adverse events as nausea and vomiting, or length of hospital stay is barely examined. The goal of our meta-analysis was to identify possibly positive effects of hypercapnia versus normocapnia in general anesthesia in adult patients.

METHODS

We conducted a systematic review of parallel-arm randomised controlled trials comparing hypercapnia versus normocapnia in adult patients undergoing general anesthesia. In July 2018 and September 2019 we searched "CENTRAL‿, "MEDLINE‿, and "Embase‿, checked reference lists of all included studies and relevant systematic reviews for additional references to trials. Two review authors independently assessed trials for inclusion, extracted data, and completed a "Risk of bias‿ assessment for all included studies.

RESULTS

Our search identified 297 records after abstract screening 30 full-text papers remained for further examination. Ten publications met our inclusion criteria and were used for narrative description of this systematic review. Three studies were eligible for the meta-analysis normocapnia versus hypercapnia with the outcomes: time to extubation and adverse events. On average, time to extubation was significantly reduced in the hypercapnia group with a mean difference 3.78 (95% CI 0.85 to 6.71). No difference was found regarding adverse events.

CONCLUSIONS

The findings of our study do not enable us to produce evidence of a positive influence of increased CO₂ partial pressure levels during general anesthesia. A well-planned, adequately powered randomized controlled trial would be desirable in the future.

Treatment of end-stage peripheral artery disease by Neuromodulation

BACKGROUND: Neuromodulation is a therapeutic option to improve limb salvage in end-stage peripheral arterial disease (PAD), but there is no consensus on indication for spinal cord stimulation (SCS) in PAD patients. OBJECTIVE: The aim of this study was to present end-stage PAD patient outcomes treated with SCS. METHODS: This study is a retrospective analysis based on a local prospective registry. Neuromodulation was performed there was: [1] no revascularisation option, [2) no septicaemia, [3) Rutherford stage 4–6. The primary endpoint of the study was limb salvage. Secondary endpoints were improvement in pain symptoms (assessed using a visual anlog scale/VAS) and improvement in walking distance. RESULTS: Limb salvage was reached in 30/34 patients (88%). Patients reported a significant reduction in pain on the 10-point VAS scale from baseline (median = 7.5, IQR = 7–8) to follow-up at 2 years (median = 0, IQR 0–2.75), p <  0.001. Walking distance also improved from preoperative (median = 50 m, IQR = 20–50 m) to follow-up at 2 years (median = 150 m, IQR 50–272 m), p <  0.001. RESULTS: SCS implantation in patients with end-stage PAD can enable limb salvage in a high percentage of cases and increase mobility due to pain reduction. The role of microcirculation in these improvements needs to be investigated in further studies.

Extracorporeal Hyperoxygenation Therapy (EHT) for Carbon Monoxide Poisoning: In-Vitro Proof of Principle

Carbon monoxide (CO) poisoning is the leading cause of poisoning-related deaths globally. The currently available therapy options are normobaric oxygen (NBO) and hyperbaric oxygen (HBO). While NBO lacks in efficacy, HBO is not available in all areas and countries. We present a novel method, extracorporeal hyperoxygenation therapy (EHT), for the treatment of CO poisoning that eliminates the CO by treating blood extracorporeally at elevated oxygen partial pressure. In this study, we proof the principle of the method in vitro using procine blood: Firstly, we investigated the difference in the CO elimination of a hollow fibre membrane oxygenator and a specifically designed batch oxygenator based on the bubble oxygenator principle at elevated pressures (1, 3 bar). Secondly, the batch oxygenator was redesigned and tested for a broader range of pressures (1, 3, 5, 7 bar) and temperatures (23, 30, 37 °C). So far, the shortest measured carboxyhemoglobin half-life in the blood was 21.32 min. In conclusion, EHT has the potential to provide an easily available and effective method for the treatment of CO poisoning.

Optimierung der chirurgischen Behandlung Brandverletzter: Auszüge aus der fachübergreifenden S2k-Leitlinie „Behandlung thermischer Verletzungen des Erwachsenen“

Hintergrund Trotz Brandschutzmaßnahmen und Aufklärung erleiden ca. 0,5 Millionen Menschen pro Jahr in Deutschland Verbrennungen. Im Jahr 2018 mussten fast 2000 Schwerstbrandverletzte in deutschen Verbrennungszentren behandelt werden. Brandverletzungen stellen eine schwerwiegende Erkrankung mit hoher Mortalität und langfristigen Folgen für den Patienten dar.

Methodik und Ergebnisse Ziel dieses Übersichtsartikels ist es, eine Zusammenfassung der derzeit gültigen Leitlinie zur Behandlung von Verbrennungen im Erwachsenenalter (https://www.awmf.org/leitlinien/detail/ll/044–001.html) zu präsentieren, wobei der Fokus auf folgenden Aspekten liegt: 1. der Akutbehandlung der Brandwunde am Unfallort, 2. der Entscheidungsfindung zur Verlegung in ein Brandverletztenzentrum, 3. der chirurgischen Wundversorgung mit Debridement und Hauttransplantation und 4. der Nachsorge. Die S2k-Leitlinie basiert auf aktueller Literatur und dem Konsens von 11 an der Behandlung Brandverletzter beteiligter Fachgesellschaften.

Zusammenfassung Dieser Übersichtsartikel enthält gewichtete Empfehlungen zur Behandlung von Brandwunden erwachsener Patienten in Deutschland. Der Artikel soll Ärzten und medizinischem Personal in der Akutsituation vor Ort und in der Klinik die Entscheidung über die notwendige Behandlung erleichtern. Hiermit soll die Behandlungsqualität für Patienten verbessert werden.

Long-Term Venovenous Connection for Extracorporeal Carbon Dioxide Removal (ECCO2R)-Numerical Investigation of the Connection to the Common Iliac Veins

Purpose

Currently used cannulae for extracorporeal carbon dioxide removal (ECCO₂R) are associated with complications such as thrombosis and distal limb ischemia, especially for long-term use. We hypothesize that the risk of these complications is reducible by attaching hemodynamically optimized grafts to the patient’s vessels. In this study, as a first step towards a long-term stable ECCO₂R connection, we investigated the feasibility of a venovenous connection to the common iliac veins. To ensure its applicability, the drainage of reinfused blood (recirculation) and high wall shear stress (WSS) must be avoided.

Methods

A reference model was selected for computational fluid dynamics, on the basis of the analysis of imaging data. Initially, a sensitivity analysis regarding recirculation was conducted using as variables: blood flow, the distance of drainage and return to the iliocaval junction, as well as the diameter and position of the grafts. Subsequently, the connection was optimized regarding recirculation and the WSS was evaluated. We validated the simulations in a silicone model traversed by dyed fluid.

Results

The simulations were in good agreement with the validation measurements (mean deviation 1.64%). The recirculation ranged from 32.1 to 0%. The maximum WSS did not exceed 5.57 Pa. The position and diameter of the return graft show the highest influence on recirculation. A correlation was ascertained between recirculation and WSS. Overall, an inflow jet directed at a vessel wall entails not only high WSS, but also a flow separation and thereby an increased recirculation. Therefore, return grafts aligned to the vena cava are crucial.

Conclusion

In conclusion, a connection without recirculation could be feasible and therefore provides a promising option for a long-term ECCO₂R connection.

Treatment of children with hyperbaric oxygenation (HBOT): a Europe-wide survey

BACKGROUND

Hyperbaric oxygenation therapy (HBOT) is used as emergency treatment for decompression sickness, gas embolism, carbon monoxide intoxication, and necrotizing fasciitis. There is low evidence and little clinical knowledge about the treatment of children with HBOT.

METHODS

We sent an internet-based questionnaire to HBO centers in Europe to gain information about their experience with children and HBOT.

RESULTS

Out of all HBO-centers who participated in the questionnaire 90% treat children analogue to adults about indication and HBOT protocol. Most treated children had life-threatening indications or the risk of organ loss. The reported rate of side effects was: 6.8% anxiety, 2.4% barotrauma, 0.9% seizure, 0.2% retinopathy and no case of pulmonary barotrauma or oxygen toxicity.

CONCLUSIONS

HBO therapy for children is present in European HBO centers. The rate of severe side effects is as low to the rates in adults; apart from this, oxygen-related seizures and anxiety are more frequent. A special focus seems necessary on the psychological management of the children, because anxiety is common depending on the age of the children. Especially for smaller children, an adequate psychological support seems essential. Prospective observational or controlled studies in children seem necessary to create relevant clinical evidence for HBOT and to observe the rate of side-effects.

Decentralized safety concept for closed-loop controlled intensive care

This paper presents a decentralized safety concept for networked intensive care setups, for which a decentralized network of sensors and actuators is realized by embedded microcontroller nodes. It is evaluated for up to eleven medical devices in a setup for automated acute respiratory distress syndrome (ARDS) therapy. In this contribution we highlight a blood pump supervision as exemplary safety measure, which allows a reliable bubble detection in an extracorporeal blood circulation. The approach is validated with data of animal experiments including 35 bubbles with a size between 0.05 and 0.3 ml. All 18 bubbles with a size down to 0.15 ml are successfully detected. By using hidden Markov models (HMMs) as statistical method the number of necessary sensors can be reduced by two pressure sensors.

Septic porcine blood does not further activate coagulation during in vitro membrane oxygenation

Objectives

For patients with a severe acute respiratory distress syndrome (ARDS), extracorporeal membrane oxygenation (ECMO) represents a life-saving measure. Frequently, patients with severe ARDS also show signs of severe sepsis. As blood contact with the membrane oxygenator surface leads to adverse effects due to insufficient biocompatibility partly caused by activation of platelets, coagulation factors and leucocytes, we hypothesized that these adverse effects would be amplified if septic blood in a preactivated state came into contact with the membrane oxygenator.

Methods

In a previously established in vitro 12-h ECMO test system (mock loop), we used septic or healthy domestic pig blood to analyse coagulation and inflammatory parameters. Sepsis was induced by a caecal ligation and puncture model in pigs.

Results

At the beginning of the mock loop experiments, the septic blood showed significantly increased thrombin-antithrombin complexes (76.9 vs 27.7 µg/l), D-dimers (1.2 vs 0.3 mg/l) and fibrinogen concentration (1.8 vs 1.5 g/l), as well as elevated extrinsic coagulation activity (shorter EXTEM-CT: 44.2 vs 57 s) and higher lactate (3.4 vs 1.5 mmol/l) and cytokine levels (interleukin-6: 827 vs 31 pg/ml) when compared with the blood from healthy animals. Despite the preactivated status of the septic blood, no further increase of coagulation activity, inflammatory response or increased oxygenator resistance was observed in comparison to the control experiments.

Conclusion

Septic porcine blood was not further activated due to the contact with an oxygenator, and no increased clot formation or biocompatibility problems were observed.

Physiological closed-loop control of mechanical ventilation and extracorporeal membrane oxygenation

A new concept is presented for cooperative automation of mechanical ventilation and extracorporeal membrane oxygenation (ECMO) therapy for treatment of acute respiratory distress syndrome (ARDS). While mechanical ventilation is continuously optimized to promote lung protection, extracorporeal gas transfer rates are simultaneously adjusted to control oxygen supply and carbon dioxide removal using a robust patient-in-the-loop control system. In addition, the cooperative therapy management uses higher-level algorithms to adjust both therapeutic approaches. The controller synthesis is derived based on the introduced objectives, the experimental setup and the uncertain models. Finally, the autonomous ARDS therapy system capabilities are demonstrated and discussed based on

D-dopachrome tautomerase in adipose tissue inflammation and wound repair

D-dopachrome tautomerase (D-DT/MIF-2) is a member of the macrophage migration inhibitory factor (MIF) cytokine superfamily, and a close structural homolog of MIF. MIF and D-DT have been reported to be involved in obesity, but there is little known about the regulation of D-DT in adipose tissue inflammation and wound healing. Subcutaneous adipose tissue was collected from 54 healthy donors and 28 donors with acutely inflamed wounds undergoing wound debridement. In addition, epididymal fat pads of mice were injected with lipopolysaccharide to study receptor expression and cell migration in vivo. D-DT protein levels and mRNA expression were significantly decreased in subcutaneous adipose tissue adjacent to acutely inflamed wounds. D-DT improved fibroblast viability and increased proliferation in vitro. While D-DT alone did not have a significant effect on in vitro fibroblast wound healing, simultaneous addition of neutralizing MIF antibody resulted in a significant improvement of fibroblast wound healing. Interestingly, expression of the MIF and D-DT receptor CD74 was down-regulated while the MIF receptors CXCR2 and CXCR4 were up-regulated primarily on macrophages indicating that the MIF-CXCR2/4 axis may promote recruitment of inflammatory cells into adipose tissue. Our results describe a reciprocal role of D-DT to MIF in inflamed adipose tissue, and indicate that D-DT may be beneficial in wound repair by improving fibroblast survival and proliferation.

[Not Available]

Skin and soft tissue infections may progress rapidly and take a fatal ending unless not treated in time. A 44-year old male patient without any pre-existing conditions got hospitalized with a bursitis ofthe right olecranon and unspecific general symptoms. Within a short period of time he became critically ill due this seemingly harmless infection. We describe our approach leading to the right diagnoses and the treatment of this unexpected progress.

Bringing obesity to light: Rev-erbα, a central player in light-induced adipogenesis in the zebrafish?

BACKGROUND

Recent studies have led to an expansion of potential factors capable of stimulating obesity. Increasing evidence indicates that environmental factors, including disturbance of circadian rhythms, also contribute to its etiology.

OBJECTIVES

To determine the effects of altered circadian rhythms on adipogenesis and to better understand how circadian and adipogenic regulatory pathways are linked, zebrafish larvae were exposed to various light/dark cycles or hypercaloric feeding (HCF).

METHODS

Clock and adipogenic gene expression was quantitative real time PCR. Adipogenesis was characterized using coherent anti-Stokes Raman scattering microscopy (CARS) and whole-mount lipid composition was analyzed by gas chromatography. The clock protein Rev-erbα and the adipogenesis-regulating protein Pparγ were localized by immunohistochemistry.

RESULTS

Zebrafish larvae exposed to continuous light (LL) had a sevenfold higher prevalence of adipocytes compared with control fish under a 14 h light and 10 h dark cycle. It was also significantly higher compared with that in HCF larvae with control light/dark cycle, which showed a 5.5-fold increase compared with control animals. Although total fatty acid content was unaffected, adipocyte lipid composition was altered in LL zebrafish. In contrast, shifting the onset and duration of the light periods did not affect adipogenesis or total fatty acid content. Gene expression analysis revealed effects of LL and HCF on circadian cyclicity, with increased expression of the clock gene period2 and altered circadian rev-erbα expression in LL larvae. Immunostaining revealed for the first time that Rev-erbα and Pparγ colocalize in adipocytes, which together with the gene expression analysis suggests interplay between Rev-erbα and Ppar isoforms.

CONCLUSIONS

The amount of light, but not shifted light/dark cycles, affected adipogenesis and lipid composition, possibly due to increased period2 expression, which, in turn, enhances Rev-erbα-regulated gene expression. As the pparβδ promoter includes three Rev-erbα binding sites, we hypothesize that pparβδ may be a direct target that ultimately activates Pparγ.

An analysis of the association between prostate cancer risk loci, PSA levels, disease aggressiveness and disease-specific mortality

BACKGROUND

Genome-wide association studies have identified multiple single-nucleotide polymorphsims (SNPs) associated with prostate cancer (PCa). Although these SNPs have been clearly associated with disease risk, their relationship with clinical outcomes is less clear. Our aim was to assess the frequency of known PCa susceptibility alleles within a single institution ascertainment and to correlate risk alleles with disease-specific outcomes.

METHODS

We genotyped 1354 individuals treated for localised PCa between June 1988 and December 2007. Blood samples were prospectively collected and de-identified before being genotyped and matched to phenotypic data. We investigated associations between 61 SNPs and disease-specific end points using multivariable analysis and also determined if SNPs were associated with PSA at diagnosis.

RESULTS

Seven SNPs showed associations on multivariable analysis (P<0.05), rs13385191 with both biochemical recurrence (BR) and castrate metastasis (CM), rs339331 (BR), rs1894292, rs17178655 and rs11067228 (CM), and rs11902236 and rs4857841 PCa-specific mortality. After applying a Bonferroni correction for number of SNPs (P<0.0008), the only persistent significant association was between rs17632542 (KLK3) and PSA levels at diagnosis (P=1.4 × 10(-5)).

CONCLUSIONS

We confirmed that rs17632542 in KLK3 is associated with PSA at diagnosis. No significant association was seen between loci and disease-specific end points when accounting for multiple testing. This provides further evidence that known PCa risk SNPs do not predict likelihood of disease progression.

Blood lead levels in scuba divers: a pilot study

INTRODUCTION

Lead is a toxic element which is known to accumulate in the body. Nevertheless, it is very widely used as a diving weight.

METHODS

Blood samples were taken from 20 recreational scuba divers to assess blood lead concentrations.

RESULTS

The last dive before blood sampling was an average of 4.8 weeks previously (range 1-18 weeks). All the samples were within the normal background range, the highest lead concentration being 44.8 µg∙L⁻¹ with an average concentration of 26.5 µg∙L⁻¹ (range 11.7-44.8 µg∙L⁻¹).

CONCLUSIONS

The results show no elevated blood lead concentrations in this group of divers compared to background levels. However, owing to the small number of divers studied and the variable, often long interval between the last dive and blood sampling, the results cannot be generalized.

Outcomes of fenestrated/branched endografting in post-dissection thoracoabdominal aortic aneurysms

OBJECTIVES

Fenestrated/branched thoracic endovascular repair (F/Br-TEVAR) is increasingly applied for atherosclerotic thoracoabdominal aortic aneurysm (TAAA); however, use in post-dissection TAAAs is still very limited. Experience with F/Br-TEVAR in the treatment of post-dissection TAAA is presented.

METHODS

Data were analysed from prospectively maintained databases including all patients with post-dissection TAAAs that underwent F/Br-TEVAR within the period January 2010 to July 2013 in two vascular institutions. Evaluated outcomes included initial technical success, operative mortality and morbidity, late survival, endoleak, aneurysm diameter regression, renal function, and reintervention during follow-up (FU).

RESULTS

A total of 31 patients (25 male, mean age 65 ± 11.4 years) were treated. Technical success was 93.5% and 30-day mortality 9.6%. Temporary spinal cord ischaemia occurred in four (12.6%) patients, with no case of permanent paraplegia. Mean FU was 17.0 ± 10 months. There were seven late deaths, all aneurysm unrelated. Estimated overall survival rates were 83.9 ± 6.7, 76.4 ± 7.9 and 71.6 ± 8.7% at 6, 12, and 18 months, respectively. Impairment of renal function occurred in two (6.4%) patients. Endoleaks were diagnosed in 12 patients during FU, including six type IB endoleaks and six type II endoleaks. Reintervention was required in seven (22.5%) patients. Mean aneurysm sac regression was 9.3 ± 8.7 mm, with a false lumen thrombosis rate of 66.7% and 88.2% for patients with a FU longer than 6 and 12 months respectively.

CONCLUSIONS

F/Br-EVAR is feasible for patients with a post-dissection TAAA. Although associated with additional technical challenges, and a significant need for reintervention, it leads to favourable aneurysm morphologic changes, and may play a more prominent role in the future for this type of pathology if long-term results confirm the good initial outcome.

Implementation of quality management in early stages of research and development projects at a university

The ultimate objective of university research and development projects is usually to create knowledge, but also to successfully transfer results to industry for subsequent marketing. We hypothesized that the university technology transfer requires efficient measures to improve this important step. Besides good scientific practice, foresighted and industry-specific adapted documentation of research processes in terms of a quality management system might improve the technology transfer. In order to bridge the gap between research institute and cooperating industry, a model project has been accompanied by a project specific amount of quality management. However, such a system had to remain manageable and must not constrain the researchers' creativity. Moreover, topics and research team are strongly interdisciplinary, which entails difficulties regarding communication because of different perspectives and terminology. In parallel to the technical work of the model project, an adaptable quality management system with a quality manual, defined procedures, and forms and documents accompanying the research, development and validation was implemented. After process acquisition and analysis the appropriate amount of management for the model project was identified by a self-developed rating system considering project characteristics like size, innovation, stakeholders, interdisciplinarity, etc. Employees were trained according to their needs. The management was supported and the technical documentation was optimized. Finally, the quality management system has been transferred successfully to further projects.

[The significance of contrast-enhanced ultrasound in vascular surgery]

BACKGROUND

Vascular contrast-enhanced ultrasound (CEUS) is a special ultrasound application without the harmful side effects of nephrotoxicity and radiation exposure. CEUS can be used for advanced diagnosis of carotid stenosis and follow-up checks of endovascular repair of abdominal aortic aneurysms (EVAR). Low-flow phenomenon in peripheral vascular disease can easily be detected by enhanced colour-coded duplex sonography (CCDS).

METHODS

The technical requirements of CEUS are explained here for the aorta, carotid, and peripheral arteries. The benefits and risks compared to computed tomography (CT), magnetic resonance (MR) and angiography are evaluated. Based on a selective review of the literature and the authors' personal experiences, CEUS is recommended for routine surveillance after EVAR.

RESULTS

CEUS is a safe method using SonoVue® (Bracco) as the only approved agent for vascular examination. Special equipment and training is necessary. In prospective studies and meta-analyses the detection and characterisation of endoleaks is comparable to that of CT imaging. Neovascularisation as a sign of carotid plaques at risk can be seen without the need for invasive treatment. Imaging of crural vessels with enhanced CCDS is a promising but rarely needed option in diabetic and renally insufficient patients.

CONCLUSION

CEUS in vascular medicine should be performed prior to other methods to avoid nephrotoxic contrast agents for the patients, especially in follow-up checks after EVAR. The time and effort required are still limiting its practical breakthrough.

Cerebral air embolism after pleural streptokinase instillation

Iatrogenic pulmonary barotrauma and cerebral arterial gas embolism (CAGE) may complicate a variety of medical procedures, such as certain types of surgery, drug administration through thoracic drainage, pneumoperitoneum, cystoscopy, bronchoscopy, etc. Hyperbaric oxygen treatment following the guidelines for CAGE in diving is the treatment of choice. Pleural streptokinase instillation is a common treatment for parapneumonic pleural effusion and may lead to CAGE. We present such a complication in a 79-year-old woman with a left-sided empyema. Neurological recovery was reasonable, but a left hemiparesis persisted. Prompt treatment of CAGE is necessary to avoid permanent injury and severe disability.

What is the significance of perioperative release of macrophage migration inhibitory factor in cardiac surgery?

Cardiac surgery is associated with release of the pleiotropic cytokine macrophage migration inhibitory factor (MIF). The trigger for MIF release has not yet been elucidated. Owing to its intrinsic antioxidative activity, MIF might reduce oxidative stress and protect from myocardial ischemia and reperfusion (I/R) injury. In the present study, patients scheduled for elective cardiac surgery (n=46) were randomized to undergo coronary artery bypass grafting either conventionally with cardiopulmonary bypass and cardioplegic arrest-induced I/R (cCABG) or in an off-pump procedure (OPCAB) with minimized I/R. We report that only patients who underwent cCABG exhibited a postoperative increase of MIF (p=0.024), while both groups showed an increase in interleukin-6. MIF release appears to be primarily mediated by I/R and to a lesser extent by inflammation. Endogenous peroxidase activity (p=0.021) and serum levels of thioredoxin (p=0.003) were significantly higher in patients who underwent cCABG after surgery. Interestingly, perioperative MIF release was associated with an enhanced antioxidant capacity and a significantly reduced postoperative incidence of atrial fibrillation (p=0.018) and acute kidney injury (p=0.048). The present study highlights the role of MIF increase during cardiac surgery in response to oxidative stress. Based on current observations, we hypothesize that intraoperative MIF secretion is due to I/R and enhances the antioxidant capacity in patients during cardiac surgery.

Haematological indices are modulated in juvenile carp, Cyprinus carpio L., exposed to microcystins produced by cyanobacterial water bloom

This study evaluated the influence of toxic cyanobacterial water blooms on the blood indices of the common carp, Cyprinus carpio L. Experimental fish were exposed to a natural population of cyanobacterial water blooms (mainly Microcystis aeruginosa and M. ichthyoblabe), which contained microcystins [total concentration 133-284 μg g⁻¹ (DW), concentration in water 2.8-7.4 μg L⁻¹]. Haematological indices showed marked changes in fish exposed to the cyanobacterial population in comparison with the control group. Statistical evaluation of the influence of cyanobacterial water blooms on biochemical indices of the juvenile carp showed a distinct decrease in albumin, alanine aminotransferase, total bilirubin, calcium, cholesterol, glucose, phosphorus and iron when compared to controls. Values of red blood counts [haemoglobin, haematocrit (PCV), mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration] and lactate were significantly increased compared to controls. After exposure to cyanobacterial water bloom, the carp were kept in clean water to monitor the persistence of biochemical indices. The influence of cyanobacterial populations on calcium, cholesterol, glucose, lactate, phosphorus and PCV persisted up to 28 days after conclusion of the experiment. Duration of exposure, toxicity and density of cyanobacterial water blooms had an important impact on individual haematological indices.

[Imaging of endoleaks after endovascular aneurysm repair (EVAR) with contrast-enhanced ultrasound (CEUS)]

Endoleaks following endovascular aneurysm repair (EVAR) are common and present a diagnostic challenge in the follow-up after EVAR. Contrast-enhanced ultrasound (CEUS) is a promising new method for the diagnosis and follow-up of endoleaks. CEUS with SonoVue allows a rapid and non-invasive diagnosis in the follow-up after EVAR. The sensitivity and specificity of conventional ultrasound compared to the multislice CT angiography is estimated to be 33-63% and 63-93%, respectively. These values can be increased through the use of CEUS in up to 98-100% (sensitivity) and 82-93% (specificity). This article describes the etiology, classification and importance of different types of endoleaks. The value of CEUS in this clinical scenario will be discussed.

Frequent expression of the high molecular, 673-bp CD44v3,v8-10 variant in colorectal adenomas and carcinomas

CD44 is a transmembrane glycoprotein involved in the interaction between cells and the extracellular matrix. A large variety of alternatively spliced CD44 variants are expressed by different tumors with possible implication for tumor progression, formation of metastasis and survival. In colon carcinomas, previous reports described higher molecular bands of CD44 transcripts in neoplastic colonic tissue, although a complete analysis of multiple combinations of CD44v transcripts were not performed. We therefore analyzed the pattern of CD44 standard and variant (v2-v10) transcripts in colorectal adenomas and carcinomas by exon-specific RT-PCR amplification and sought CD44v transcripts specific for colonic neoplasias. Our data indicate that CD44 standard transcripts, including the epithelial form (C-v8,v9,v10-C) corresponding to a 720 bp transcript, were detected in 2/38 (5.2%) samples of normal mucosa, 20/20 (100%) adenomas and in 21/33 (63%) colorectal carcinomas. High molecular CD44v3,v8-10 (673 bp) transcripts were found in 2/33 (6%) samples from normal mucosa, 19/20 (95%) from adenomas and in 29/31 from colorectal carcinomas (93%). Similar CD44v3,v8-10 transcripts were detected in five from seven colorectal liver metastases, while normal liver did not contain high molecular CD44v3 variants. The same CD44v3,v8-10 (673 bp) variant was detected in HT-29 human colon carcinoma cells. Direct sequencing of the CD44v3 (673 bp) transcript in samples from colorectal carcinomas and HT-29 cells confirmed the assumed CD44v (-C-v3-v8-v9-v10-C-) cDNA sequence. Analysis of other CD44 variant transcripts (v4-v10) using exon specific primers were less frequently associated with colorectal neoplasias. These data report for the first time frequent expression of neoplasia-associated CD44v3,v8-10 variants in colorectal adenomas and carcinomas supporting the role of increased CD44 variant expression as an early event in colorectal carcinogenesis. The described CD44v3,v8-10 (673 bp) variant might be relevant for diagnosis and treatment of colorectal cancer.

[Assisted circulation: an overview from a clinical perspective]

A higher grade cardiac failure is associated with poor prognosis. In addition to medical conservative treatment and traditional cardiac surgery, in the past years different forms of an assisted circulation evolved. Short-term devices serve to bridge an acute life-threatening situation. The chosen system is dependent on the anticipated clinical course. It is possible to fall back on slightly assisting techniques up to a complete takeover of the cardiac pump function. In the case of severe cardiac failure, the question for transplantation has to be addressed because transplantation is the treatment of choice to date. For an assisted circulation in cases of chronic congestive failure, devices of different generations are available. First generation pulsatile systems are used for assistance of the left ventricle and results have been shown to be superior to medical therapy (REMATCH). With second generation continuous-flow systems, results regarding infections, thromboembolism and also quality of life appear to be further improved. Contact-free centrifugal pumps as third generation systems are in clinical evaluation. So-called "total artificial hearts" are successfully used for bridge-to-transplantation. Taken together, a graded safe treatment of cardiac failure is available today. In the near future, it could be possible to reach results similar to those of cardiac transplantation.

[Relevance of ESBL-producing pathogens for clinical surgery: diagnostics, therapy, and prevention]

BACKGROUND

Multiresistant, extended spectrum beta lactamase (ESBL)-producing pathogens are an increasing problem in daily clinical life. This paper summarizes the development of resistance as well as epidemiology, diagnostics, and treatment of ESBL-producing micro-organisms. We analyzed microbiological data collected at the Grosshadern Clinic in Germany between 1996 and 2007, in order to assess the importance of these micro-organisms to medical practice and surgical care units.

PATIENTS AND METHODS

Pathogens were isolated from 28,894 patients with Escherichia coli and 10,903 with Klebsiella pneumoniae pathogens between 1996 and 2006 and tested for ESBL production. For the year 2007 we have analyzed the complete spectrum of ESBL-producing pathogens and their distribution to different departments of the clinic. The agar diffusion test with five cephalosporins and an automated detection system (BD Phoenix) were used for screening purposes. Positive results were verified with the E- and double-disc agar diffusion tests.

RESULTS

The most important pathogens isolated from patients were E. coli and K. pneumoniae. Analysis of ESBL-producing E. coli pathogens from 1996 to 2006 showed the prevalence increasing from 0% to 4.1%. For ESBL-producing K. pneumoniae, we also found a prevalence rising from 0.3% in 1996 to 6.6% in 2006. For the year 2007 a further increase in ESBL-producing pathogens was detected, reaching 182 cases, with 118 of ESBL-producing E. coli (5.7 %) and 39 of ESBL-producing K. pneumoniae (7.4%). Of these, 24 cases with E. coli and nine with K. pneumoniae were surgery patients (20% and 23%, respectively).

CONCLUSION

The results show an increasing prevalence of ESBL-producing pathogens in hospitalized patients and in surgical departments. The resulting rise in treatment costs and patient risk require thorough knowledge of risk factors, therapy, and preventive measures.

[Intensive care medicine as a component of the compulsory medical curriculum. Evaluation of a pilot curriculum at the University Hospital Aachen]

BACKGROUND

In order to provide early achievement of practical experience during medical education, the medical faculty of the university Aachen has developed a new medical school curriculum which was offered in 2003 for the first time. In this curriculum anaesthesiology became a compulsory subject with practical training both in the operation theatre and in emergency medicine. Accordingly, a practical course in the field of intensive care medicine has also been designed with respect to the planned schedule and personnel resources. This course was evaluated by both students and teaching staff in a written, anonymous form as a quality control.

METHODS

A dedicated course was developed for medical students of the 8th and 9th semesters. In this course comprised of 6 students and lasting 1 week, practical training is provided by intensive care physicians and accompanied by theoretical lessons focusing on the definition, diagnosis, therapy and prophylaxis of sepsis, essentials of mechanical ventilation and patient presentation at the bedside during daily rounds. On the last day of training students were required to present patients by themselves thereby recapitulating the acquired knowledge. In the summer semester 2007 this intensive care training course was offered for the first time. All participating 83 students and 23 physicians involved in teaching evaluated the course with marks from 1 to 6 according to the standard German school grading system using an online questionnaire.

RESULTS

Students rated the course with 1.6+/-0.7 (mean +/- SD) for comprehensibility, with 1.6+/-0.7 for structural design, and with 1.7+/-0.7 for agreement between teachers. They graded their personal learning success with 1.7+/-0.7. With a cumulative mark of 1.7+/-0.6, the course was ranked as 1 of the top 3 courses of the medical faculty from the very beginning. The majority of the teaching staff (80%) appreciated the focus on few selected teaching subjects. However, comprehensibility, structural design, agreement between teachers and personal learning success were graded one mark worse than by the students.

CONCLUSIONS

According to the results, efficiency and acceptance of intensive care training courses were high. Major criteria for the high grading were a limited number of participants, the focus on few subjects, and a clear structural design. However, according to several personal notes from the students, simulation-based sessions and written teaching material might further improve success of this course.

Butyrate-induced alterations of phosphoinositide metabolism, protein kinase C activity and reduced CD44 variant expression in HT-29 colon cancer cells

Initiation of cell growth and neoplastic transformation frequently involves activation of growth factor receptor-coupled tyrosine kinases and stimulation of the phosphoinositide second messenger system. Altered expression of CD44 variants was reported in several malignant tumor types with possible implications for tumor progression and prognosis. CD44 variant expression was reported to be associated with second messenger activation and differentiation. We therefore investigated the effects of butyrate-induced short-term differentiation on phosphoinositide signaling, phospholipase C and protein kinase C activity and alteration of CD44 variant expression in human HT-29 colon carcinoma cells. HT-29 cells were cultured with sodium butyrate for 6 days. Phosphoinositide turnover was measured by [32P]orthophosphate incorporation and phospholipase C activity by determination of the release of [3H]inositolphosphates from [3H]myoinositol prelabeled cells. Protein kinase C activity was determined by histone III-S phosphorylation, PKC subtype expression by RNase protection analysis, and CD44 variant expression was determined by RT-PCR using variant-specific primers. Treatment of HT-29 human colon carcinoma cells with sodium butyrate caused a dose-dependent inhibition of cell proliferation (IC50, 2.5 mM) with morphologic signs of an enterocytic differentiation following 6 days of treatment. The phosphoinositide turnover as determined by 32P-incorporation under non-equilibrium conditions showed a 30-40% inhibition of labeled phosphoinositides and phosphatidic acid and a dose-dependent inhibition of cholinergically stimulated phospholipase C activity as a secondary event following butyrate-induced enterocytic differentiation. However, long-term incubation of HT-29 cells with phorbol ester or an inhibitor of classical and novel PKC subtypes did not affect cell proliferation. In butyrate-treated HT-29 cells activation of calcium-dependent protein kinase C by cholinergic stimulation or phorbolester treatment induced an increase in membrane-bound cPKC activity, while expression of distinct high- molecular CD44 variant transcripts v3 (670 bp), v5 (940 bp) and v8 (535 bp) were drastically reduced after butyrate pretreatment. Enterocytic differentiation of HT-29 colon carcinoma cells seems to be associated with alterations in phosphoinositide resynthesis, phospholipase C activity and ligand/receptor-induced PKC translocation. The observed reduction of distinct high-molecular CD44v3, v5 and v8 variants following butyrate-induced differentiation indicates an association of specific CD44 variant expression with the malignant phenotype of HT-29 colon cancer cells, thus being possible targets for new diagnostic and therapeutic strategies.

Imaging of endoleaks after endovascular aneurysm repair (EVAR) with contrast-enhanced ultrasound (CEUS). A pictorial comparison with CTA

Endoleaks following endovascular aneurysm repair (EVAR) are common and present a diagnostic challenge in the follow-up after EVAR. Contrast-enhanced ultrasound (CEUS) with low mechanical index (low MI) is a promising new method for the diagnosis and follow-up of endoleaks. CEUS with SonoVue allows a more rapid and noninvasive diagnosis, especially in critical patients owing to its bedside availability. This review describes the etiology, classification and importance of different types of endoleaks and compares CEUS findings with computed tomography angiography (CTA), allowing the reader to appreciate the usefulness of CEUS in this clinical situation.